Side Looking Occupancy Sensor

ABSTRACT

A side looking occupancy sensor is incorporated in a conventional wall switch mounted into a switch box adjacent to a door. The side-looking proximity sensor preferably is mountable to either side of the doorjamb to make the side-looking proximity sensor face the door opening. During operation, the side-looking sensor monitors the door movement or senses the passage of a person for indication that a person is entering or leaving the space. Entry and exit determination is made based on activation of the side-looking sensor.

RELATED APPLICATIONS

This application claims priority from U.S. Provisional PatentApplication 61/794,802 filed Mar. 15, 2013.

FIELD OF THE INVENTIONS

The inventions described below relate to the field of electricalcontrols and more specifically, sensors for automatically controllingelectrical loads such as lighting.

BACKGROUND OF THE INVENTIONS

Occupancy sensors mounted in a doorjamb are known in the art.20060176697 (application Ser. No. 11/053,554) to Arruda describes usingan off-the-shelf combination light and sensor wall switch sensor thatdetects when the door is opened/closed to turn the light on/off in whichthe sensor and light are mounted together in a special structure that ismounted to or near the door frame or jamb. U.S. Pat. No. 6,023,224 toMeyvis describes a similar system that can be mounted within or to adoor frame and includes a motion sensor. Sun9 offers a doorjamb mountedoccupancy sensor that purports to count people entering and exiting (twodifferent functions) so that lighting may be controlled instantaneously,particularly on exit of the last person. This is counter to typicalmotion-based occupancy sensors that assume a space is empty due to lackof motion (or sound or other monitored event). All of these systemssuffer from the unneeded complexity of requiring special doorjambs orcomplicated mounting of special assemblies into or on to a door jamb.

SUMMARY

The devices and methods described below provide for a side lookingoccupancy sensor incorporated in a conventional wall switch mounted intoa switch box adjacent to a door opening. The side-looking proximitysensor preferably is mountable to either side of the doorjamb to makethe side-looking proximity sensor face the door opening. Duringoperation, the side-looking sensor monitors the door movement or sensesthe passage of a person for indication that a person is entering orleaving the space. Entry and exit determination is made based onactivation of the side-looking sensor.

The invention resolves issues of counting-type occupancy sensors bytaking advantage of the normal position of a wall switch relative to adoor. In most installations, a wall switch is adjacent the door,typically within one foot of the edge of the door opening.

The side looking sensor has two zones of monitoring: a first zone closeto the door opening; and a second zone at a slight distance away fromthe door opening into the room. This allows determination of direction,e.g., if the first zone is activated before the second zone, the personenters. If the second zone is activated first, then the person isexiting. A counter is incremented for entering and decremented forexiting. When the counter goes to zero, no one is left in the room andthe connected loads may be powered off.

A standard motion sensor may also be provided that maintains lightingbased on standard occupancy sensing (e.g., passive infrared, ultrasound,sound, etc.) as may a daylight sensor, as both are known in the art. Thestandard motion sensor may optionally be used to confirm when no one isleft in the room. When no one is in the room, the lights are preferablyturned out to save energy.

A side looking occupancy sensor includes a load control device having ahousing and controller, one or more active infrared proximity sensors inthe housing and operably coupled to the controller along with one ormore optical elements optically coupled to each of the one or moreinfrared proximity sensors and a passive infrared sensor in the housingand operably coupled to the controller.

A side looking occupancy sensor controlling the application ofelectrical power to electrical loads in a room with a doorway includes aload control device having a housing and controller wherein the loadcontrol device is mounted adjacent to the doorway and one or more activeinfrared proximity sensors in the housing and operably coupled to thecontroller for sensing people passing through the doorway. One or moreoptical elements are optically coupled to each of the one or moreinfrared proximity sensors and a passive infrared sensor is included inthe housing and operably coupled to the controller for sensing whenpeople remain and leave the room.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a wall switch with the occupancy sensorincluded.

FIG. 2 is a perspective view of a room with a door and electric loadscontrolled by the wall switch/occupancy sensor of FIG. 1.

FIG. 3 is a front view of the wall switch/occupancy sensor of FIG. 1.

FIG. 4 is a side view of the wall switch/occupancy sensor of FIG. 1.

FIG. 5 is a cross section view of the wall switch/occupancy sensor ofFIG. 1 taken along A-A.

DETAILED DESCRIPTION OF THE INVENTIONS

Sensor switch 10 of FIGS. 1 and 2 includes one or more proximity sensorssuch as sensors 12 incorporated into housing 11 to detect the opening ofdoor 1 and/or the entry or exit of one or more persons into or out ofroom 3.

The term wall switch will be used to refer to any load control devicethat is mounted on a wall such as wall 4 near a door opening such asdoorway or opening 6 at about ½ the height 8 of the opening into whichthe device may be implemented. Proximity sensing technology, preferablysuitable for detecting people, is employed such that the proximitysensing zone or zones are oriented off of the side of the switch towardthe door opening.

The side looking proximity sensor 12 has two zones of monitoring: afirst monitoring zone 13 close to the door opening; and a secondmonitoring zone 15 at a slight distance away from the door opening intothe room. This allows determination of direction, e.g., the sensor forfirst zone 13, sensor 12A, is activated before the sensor for secondzone 15, sensor 12B the person enters. If second zone 15 is activatedfirst, then the person is exiting. A counter, microprocessor, controlleror other suitable device such as controller 16 are connected to andreceive signals from active sensors 12 and secondary sensor 18 tocontrol operation of load control device 10. Controller 16 is programmedto track persons entering and exiting room 3 as well as implementsuitable control algorithms such as control algorithm 21. When thecontroller determines that no persons are left in the room, theconnected loads, loads 17 may be powered off.

Secondary sensor 18 maintains the application of electrical energy tothe loads based on standard occupancy sensing (e.g., passive infrared,ultrasound, sound, etc.) and may a daylight sensor, as both are known inthe art. Signals from secondary sensor 18 may optionally be used toconfirm when no one is left in the room. When no one is in the room, thelights are preferably turned out to save energy. For example, Once sidelooking proximity sensor 12 at the doorway is triggered, it sends acorresponding signal to the controller, and occupancy is confirmed bysecondary sensor 18 which sends a corresponding occupancy signal to thecontroller, controller 16 sets, selects or establishes a very longtime-out period and there is very little chance of a faults off. If sidelooking proximity sensor 12 at the doorway is triggered, sending acorresponding signal to the controller, and occupancy is not confirmedby secondary sensor 18 which sends a corresponding non-occ signal to thecontroller, controller 16 sets, selects or establishes a very shorttime-out period. Literally in seconds in some residential applicationlike a closet but longer in an office but this is where the counting ofaddition entries can be used.

The proximity sensors such as sensors 12A and 12B of may adopt anysuitable technology such as infrared consisting of a transmitter andreceiver. These may be narrow beam transmitters or receivers, or theymay employ lenses 19, such as a Fresnel lens, to restrict the size anddirection of the monitored zone. Positioning of the side looking sensorswould need to account for the geometry at wallbox 5 and door opening 6,and specifically the likely presence of trim or molding 2 around thedoor opening. Side looking sensors 12 need to be oriented such thattheir monitoring zones, zones 13 and 15, are not blocked by this trim.

Typically, wall switches include a face plate or wall plate that isdecorative but that also serves a safety function. Typically, wallswitches are designed such that they are flush with the wall plate atthe perimeter of the opening in the wall plate. In such cases, the wallswitch may need to be designed to protrude slightly away from the wallplate to allow the transmitter and receiver to be oriented toward thedoorway and not be blocked by the wall plate. A protrusion of 1-2 mm ispreferred to maintain the decorative look of the wall switch and wallplate, but smaller protrusion for just the transmitter and/or receivermay be done and integrated with decorative features in the wall switchor wall plate, e.g., a sea shell scalloped design normally lends itselfto raised areas suitable for the transmitter or receiver. Alternatively,recesses or channels may be formed in the wall plate to allow the energyto be directed without being blocked, and these recesses or channels maybe functional in that they may help direct or collect the energy.

A first monitored zone 13 is established very close to the door opening.The transmitter sends a beam of infrared light out across the dooropening. If a person is coming through the doorway, the beam isreflected off of the person and a portion of the reflected beam ispicked up by the receiver. The infrared beam may be continuous orpulsed.

If the infrared beams are pulsed, the first and second zone infraredtransmitters may pulse at different frequencies to reduce the effect ofany crosstalk or cross-contamination in the corresponding receivers. Twotransmitters such as transmitters 12A and 12B may be used, but only onereceiver such as receiver 20 as illustrated in FIG. 5, by coordinatingthe transmission and reception, e.g., transmitting on the first zone andwaiting a period of time for a reflection, then alternating to thesecond zone, or by using different frequency transmitters, etc. Thesingle receiver may require a lens, mirror or light pipe to pick upsignals from each transmitter. A single transmitter and receiver may beused if they may be adjustably oriented to each of the first and secondzones, e.g, by rotating the transmitter with a small gear assembly ormotor or by rotating a lens. One or more mirrors may or light pipes maybe used to direct the transmitted and received energy and these may alsobe adjustable. Transmitters and receivers, or their lenses or mirrors,may be manually rotatable within a limited range to make adjustments tothe direction of each zone to maximize performance, e.g., the first zonemay be adjusted slightly closer to the doorway and the second zone maybe adjusted slightly more away from the doorway.

Normally, the transmitter and receiver, or their respective lenses ormirrors, would be oriented more or less orthogonally to the verticalorientation of the wall switch, that is, side looking straight out theside of wall switch. This orientation with a narrow beam system wouldwork with adults but may not see small children. This may be addressedin several ways. Multiple transmitters may be provided, e.g., oneoriented orthogonally and one angled downward. A single transmitter orits lens may be permanently oriented at a downward angle, but care mustbe taken to not mistake leg movements during walking for multiplepersons entering or exiting a space. The transmitter and receiver may bedesigned to spread the beam across the lower portion of the doorway andreceive reflected beams from the same area, e.g., using suitable lensesor mirrors. A single lens may have elements or lenslets that act tospread the transmitter beam out to the monitored zone and other elementsthat act to focus received energy on to a receiver.

Multiple people going through a doorway in either direction may beaccounted for by taking the net of activity in the first and secondzones. If the first zone has more activity, that would indicate a netexit and the count may be decremented, and visa versa. Other algorithmsfor handling multiple people are anticipated.

Alternatively, light pipes may be provided that blend with the wallplate or are built into the wall plate. These light pipes serve to sendand receive the infrared energy used for proximity sensing.

Low power ultrasound may be used for proximity sensing at the doorway.It is preferred that two different ultrasonic frequencies be used toavoid cross talk; however, the same frequency may be used if theultrasound is pulsed and pulsing for each zone is separated in time soas to reduce crosstalk. Small horn structures may be used to direct theultrasonic energy to the monitored zone and to receive the reflectedultrasonic energy from that zone. Microwaves may also be used but mayrequire special horns to properly direct and collect the energy. Othercommon occupancy sensing technologies may be adapted, such as a videocamera based sensor configured to monitor the larger zone defined as thearea between and including the first and second zones. Such a camerasensor may process the image to determine direction and keep a runningcount of entries and exits.

A single side looking sensor may be configured to mount to either sideof the door in a number of ways. The sensor may be designed to simply bemounted upside down to go from the left side of a door to the right sideof that door; small adjustments may be needed to ensure the energy iscorrectly directed in the new position. A bezel assembly or othersuitable optical element at the front facing part of the side lookingsensor, may include buttons and lenses or light pipes or mirrors, may beprovided and changed out; a standard bezel assembly may be suitable forthe left side and the alternate bezel assembly may be suitable for theright side.

A side looking sensor may be mounted to a wall that is immediatelyadjacent a doorway and orthogonal to the doorway, such as may occur ifthe door is placed at the end of a hallway that leads into a largerspace. In this configuration the energy used for detection must bedirected and collected from an area that is directly in front of thesensor or slightly to one side and not in a side looking direction. Thetechniques described above may be used to direct and collect thisenergy.

A single zone proximity sensor may be used in coordination with anysuitable occupancy sensor that may be built into the wall switch withthe side looking sensor such as sensor 18 or it may be a separatedevice, sensor 22, e.g., a ceiling mounted occupancy sensor if a wiredor wireless communication path is established between the side lookingsensor and occupancy sensor. The occupancy sensor may be any suitabletype, such passive infrared, ultrasound, sound, gas (e.g., CO2),microwave, video based or combinations thereof. The occupancy sensordetermines when there is no one in the space for a period of time, whichmay be adjustable. This establishes a known starting point for countingpurposes. The level of activity measured by the occupancy sensor helpsdetermine if people have entered or left the space, along with theproximity sensor activity. The first triggering of the proximity sensorindicates a person has entered the space (count is one), and this can beconfirmed by the activity level measured by the occupancy sensor. Thenext signal at the proximity sensor is compared against the occupancysensor activity to determine if there was an exit (no subsequentoccupancy sensor activity, count goes to zero) or another entry (moresubsequent occupancy sensor activity, count goes to two).

Two or more side looking switches or side looking occupancy sensors maybe mounted into a space with two or more doors. They may keep track oftheir sensing zones (doorway and a portion of the space, such as a largeconference room) independently, or they may be connected together, e.g.,via a traveler wire, multi-wire cable or wirelessly as is known in theart, to send suitable messages to each other to share occupancyinformation and coordinate the control of lighting in the space. Thismay allow one of the side looking devices to turn off or dim lighting inits zone or monitored space if it believes there are no more peoplethere while the other side looking device maintains lighting if itcontinues to believe that people are in its monitored space.

While the preferred embodiments of the devices and methods have beendescribed in reference to the environment in which they were developed,they are merely illustrative of the principles of the inventions. Theelements of the various embodiments may be incorporated into each of theother species to obtain the benefits of those elements in combinationwith such other species, and the various beneficial features may beemployed in embodiments alone or in combination with each other. Otherembodiments and configurations may be devised without departing from thespirit of the inventions and the scope of the appended claims.

We claim:
 1. An occupancy sensor comprising: a load control devicehaving a housing and controller; one or more active infrared proximitysensors in the housing and operably coupled to the controller; one ormore optical elements optically coupled to each of the one or moreinfrared proximity sensors; and a passive infrared sensor in the housingand operably coupled to the controller.
 2. An occupancy sensorcontrolling the application of electrical power to electrical loads in aroom with a doorway, the occupancy sensor comprising: a load controldevice having a housing and controller wherein the load control deviceis mounted adjacent to the doorway; one or more active infraredproximity sensors in the housing and operably coupled to the controllerfor sensing people passing through the doorway; one or more opticalelements optically coupled to each of the one or more infrared proximitysensors; and a passive infrared sensor in the housing and operablycoupled to the controller for sensing when people remain and leave theroom.
 3. The occupancy sensor of claim 1 wherein: the controller isprogrammed to; apply power to the electrical loads in response to afirst signal from the one or more active infrared proximity sensors anda first signal from the passive infrared sensor; and to establish afirst time-out period; and apply power to the electrical loads inresponse to a first signal from the one or more active infraredproximity sensors and a second signal from the passive infrared sensor;and to establish a second time-out period with the second time-outperiod is shorter than the first time-out period.
 4. The occupancysensor of claim 2 wherein: the controller is programmed to; apply powerto the electrical loads in response to a first signal from the one ormore active infrared proximity sensors and a first signal from thepassive infrared sensor; and to establish a first time-out period; andapply power to the electrical loads in response to a first signal fromthe one or more active infrared proximity sensors and a second signalfrom the passive infrared sensor; and to establish a second time-outperiod with the second time-out period is shorter than the firsttime-out period.
 5. An occupancy sensor system for controlling theapplication of electrical power to electrical loads in a room with adoorway comprises: a load control device having a housing and controllerwherein the load control device is mounted adjacent to the doorway; oneor more active infrared proximity sensors in the housing and operablycoupled to the controller for sensing people passing through thedoorway; one or more optical elements optically coupled to each of theone or more infrared proximity sensors; and a passive infrared sensor inthe room and operably coupled to the controller for sensing when peopleremain and leave the room.
 6. The occupancy sensor of claim 5 wherein:the controller is programmed to; apply power to the electrical loads inresponse to a first signal from the one or more active infraredproximity sensors and a first signal from the passive infrared sensor;and to establish a first time-out period; and apply power to theelectrical loads in response to a first signal from the one or moreactive infrared proximity sensors and a second signal from the passiveinfrared sensor; and to establish a second time-out period with thesecond time-out period is shorter than the first time-out period.